During manufacturing of electronic products, a component such as an integrated circuit (IC), or ‘chip’, of semiconductor or other suitable material may be conveyed towards a destination substrate such as a conventional circuit board, or a flexible circuit board, e.g. a plastic film, paper or cardboard substrate, using a variety of methods. Depending on the scenario, such procedures typically comprise picking a chip from a source location, optionally changing the orientation of the chip and ultimately placing the picked chip at a target location on the substrate. Picking may be suction-assisted, for instance.
In FIG. 1, with reference to arrangement 100 one exemplary scenario is shown for further clarification. Flip chip packaging is nowadays often preferred over more traditional SMDs (surface mount device) requiring e.g. wire bonding due to evident cost, size, electrical performance, I/O connection flexibility and durability advantages. So, a plurality of e.g. solder bumped flip chips 103 may have been originally manufactured as portions of a common silicon wafer. The larger wafer defining the plurality of chips may have been then sawn or cut into individual chips during ‘dicing’. Alternatively, dicing could take place during or at the beginning of a pick-and-place procedure reviewed more thoroughly below.
Reverting to the details of the figure, at 100A, a robotic manipulator arm 104 or other actuator is used to pick up each flip-chip 103 (notice the bumps 105 depicted on the top surface of the chips), one at a time, from the diced wafer located on a source substrate, such as a carrier membrane, or a container, such as a tray, 102. The arm 104 comprises a head for the purpose, optionally exploiting vacuum suction to hold the chip 103.
At 100B, the manipulator arm 104 rotates the picked up chip 103 upside down, the bumps 105 thereby facing downwards, and hands over the rotated chip 104 to a bonding or mounting arm 106 that, at 100C, aligns and disposes the chip to a target location on the destination substrate 111. The arm 106 may execute a so-called place-and-press function, which besides placing the chip at the right location on the substrate 111, also presses it against it so that both mechanical and electrical attachment is secured. The substrate may have been provided beforehand with a circuit layout including e.g. printed conductors and contact areas 108 for accommodating a number of chips. Further, flux may have been spread on the solder bumps 105 or contact areas 108 during the process, and/or provided in the material of the solder bumps 105 itself.
Publication WO2012049352 discloses a method and apparatus for chip picking and placement in accordance with the afore-explained procedure of FIG. 1. The surface area 108 of the substrate 111 on which the chips 103 are attached has been initially provided with material that has lower melting temperature than the chips 103 can tolerate without being damaged, with reference to low-temperature solder or similar material, whereupon each chip 103 can be safely heated to an elevated temperature that still induces no damage to the chip, but causes the material of the area 108 and/or solder bumps 105 of the chip 103 to melt and secure the bonding while the chip 103 is pressed against the surface 108 of the substrate 111.
The procedure disclosed in the aforementioned publication '352 is obviously highly advantageous as it generally accelerates the bonding procedure and the use of e.g. conventional surface mount reflow ovens can be omitted.
Notwithstanding the evident benefits the modern manufacturing and mounting techniques of components, such as the discussed flip chip solutions, offer to the state of the art, continued optimization of component assembly processes is still generally desired in terms of manufacturing costs, complexity, production times, and yield, i.e. multiple interrelated factors. Whether the optimization is worth the trouble depends, of course, on the scale of the manufacturing activity. As the related business grows, also the technical black spots arising from sub-optimum processes rise in importance and eventually form different types of actual bottlenecks in the production chain.
Accordingly, depending on the use scenario, certain operations regarding the handling of flip chips or other electronic or non-electronic components may be more problematic or simply more undesired than the rest, even if providing completely satisfactory results in terms of production accuracy or product reliability. With robotic manipulators such as aims for picking, treating and/or placing components, rotational movement particularly if to be combined with or succeeded or preceded by translational movement in three dimensions may be both technically challenging and costly to implement in a high speed production line with sufficient long-term reliability and accuracy. It may thus establish one bottleneck of the system.
For example, the arms 104 and 106 of the arrangement 100 may have been configured for both rotational and translational (sideways or vertical) movement to be able to comprehensively execute the required chip picking, chip flipping, and chip mounting procedures as contemplated hereinbefore. Such versatile aims 104, 106 are generally feasible, and in many contexts cause no real headache, but occasionally together with increase in the production output, the diverse 3d trajectories potentially involving both rotation and translational movement may at certain point begin to limit the process speed and make it unnecessarily complex, costly, inaccurate and even unreliable.